The Office International des Epizooties (OIE) is the World Animal Health Organisation created in 1924 in Paris. The following activities have been started in order to promote standardisation of biologicals: a) preparation of the OIE Manual of Standards for Diagnostic Tests and Vaccines; b) organisation of Reference Laboratories for diseases of Lists A and B; c) establishment, in cooperation with WHO, FAO and IAEA, of international standards for diagnostic tests with particular reference to the ELISA. The Manual will be distributed worldwide in 1992 and 1993 and this will contribute to an internationally unified approach to diagnosis and immunoprophylaxis, in other words to international harmonisation of veterinary biologicals. It is planned that future OIE Reference Laboratories, now being organised, will supply the necessary standards.